The present invention relates to a process for the conversion of light hydrocarbons that are typically volatile at standard conditions of temperature and pressure into hydrocarbons that are readily transportable at standard conditions.
In many remote areas of the world, light hydrocarbons are extracted from the earth along with crude oil. In these remote areas, the need for such hydrocarbons is non-existent. Recovered hydrocarbons must be transported to refineries and the like by pipelines or by ship. This poses a problem where light hydrocarbons such as C.sub.2 -C.sub.6 aliphatic hydrocarbons are involved. Such hydrocarbons are not readily transportable and typically require special handling in specially designed ships.
Quite often, the amounts of these materials produced along with the difficulty in transporting these materials to a market by pipeline or vessel results in these valuable materials being flared as waste gases or reinjected back into the well. One approach that has been taken to eliminate this problem is to convert these volatile, low molecular weight hydrocarbons into higher molecular weight hydrocarbons which are readily transportable via the crude pipelines to markets. One such process for upgrading light hydrocarbons is the dehydrocyclodimerization process.
The dehydrocyclodimerization process produces a highly aromatic product from a feedstock comprising C.sub.2 -C.sub.6 aliphatic hydrocarbons. Two relatively significant by-product streams comprising hydrogen, and C.sub.1 -C.sub.2 hydrocarbons are also produced. In remote areas of the world and in the absence of refinery processes requiring hydrogen, the hydrogen and light hydrocarbon by-products must be disposed of typically by burning. Hydrogenation of the aromatic product has been used to maximize the amount of transportable products obtained from a light volatile hydrocarbon feed while minimizing the production of unusable light by-products. Hydrogenating the aromatic product has the disadvantage of reducing the octane of transportable product. Therefore, a process that would provide a high volume of transportable product having a high octane is very desirable. In addition, due to toxicity concerns it would also be desirable to eliminate benzene from the transported product.